The automotive vehicle equipment unit is intended to constitute a structuring equipment part in an automotive vehicle, such as shelving, flooring or lateral trim or lining for the trunk.
Current coverings and liners for flooring, shelving or lateral trim lining for the trunk of an automotive vehicle, are often considered easily soiled, having little to no abrasion-resistance and difficult to clean. They require the addition of floor/surface mats or plastic heel pieces.
The current coverings and liners for automotive vehicle equipment units generally comprise fiber bonded needled or tufted carpets or mats, warp knit type textiles for use as cladding for shelving or roof panels, sheets of TPO (Thermoplastic PolyOlefin) plastics possibly grained or cladding sheets made of flexibilized wood.
However, these coverings and liners present either properties that are limited in terms of abrasion resistance, or problems related to ease of cleaning.
There therefore exists a need for an economical liner, which is thermoformable and having a controlled sound absorption.
Fabrics constituted of yarns, comprising a sheath of polyvinyl chloride (PVC) and a core made of semi-crystalline polyethylene terephthalate (PET) are already known. The term ‘semi-crystalline PET’, is used to refer to PET having, for example, a degree of crystallinity that is higher than 20%.
Such fabrics are strong and solid and have very low deformability. These fabric materials are appropriate for floor coverings in the housing and habitat development sector and for exterior applications because of their high resistance to water and their mechanical strength. In addition, the PET core presents a rigidity that facilitates the weaving of the filament yarn.
However, such types of fabrics are not used for the manufacture of automotive vehicle equipment parts or units with irregularly shaped forms due to constraints related to thermoforming thereof. Indeed, such types of fabrics are not deformable under the operating conditions of the molding or formation lines and with the composite bodies generally associated with the coverings and liners.
In fact, when the vehicle equipment part/unit to be formed is an element of a sound-absorbing complex in the vehicle flooring, it is necessary to have a covering or liner that is capable of conforming to the formed shape of the complex. For example, the floor coverings are combined with other products, such as heavy weights or felts for acoustics related reasons and/or in order to give them sufficient stiffness that will make possible the appropriate positioning thereof within the vehicle quickly on the assembly lines.
The composite body covered by the covering or liner comprises, for example, a layer of ceramic fibers, for instance, glass fibers, with the ceramic fibers being embedded in a thermoplastic polymer matrix composed of polyolefin, such as polypropylene. The commercial term “Sommold’ is used to refer to this type of material. This material being constituted of glass fibers and polypropylene, degrades very rapidly above 200° C.
However, the softening temperature of the PET is about 230° C. The semi-crystalline PET is thermoformable only from 230° C. onwards which renders impossible the combination thereof with the Sommold and therefore the forming thereof for use in the context of automotive coverings and liners. At 160° C., which is the melting point temperature of polypropylene, and temperature for the forming of Sommold, the PET is not thermoformable. At 230° C., the PET is thermoformable but the polypropylene degrades resulting in the equipment part having poor mechanical properties. Furthermore the PVC which constitutes the sheath of the filament yarns of the fabric also degrades very rapidly at temperatures above 200° C.
The Sommold and the fabric of the type described here above are thus incompatible and it is not possible to combine them in a composite equipment unit.